Grain yield and yield components in canola according to nitrogen sources and rates

Abstract

The objective of this work was to evaluate the response of canola to nitrogen sources and rates applied at sowing. The experiment was carried out on a dystroferric Red Ferralsol, with a very clayey texture. A randomized complete block design was used, in a 7x2 factorial arrangement, with seven N rates applied on soil surface at sowing (0, 20, 40, 60, 80, 100, and 120 kg ha^‑1), two N sources (ammonium sulfate and urea), and four replicates. The experiment was carried out with the Hyola 61 hybrid for two years, and the following variables were evaluated: plant height, number of plants per square meter, shoot dry matter mass, pod mass per plant, weight of a thousand grains, grain yield, and protein and oil contents in seeds. The variables were not affected by the N sources. The highest grain yield is obtained with 88 kg ha^‑1 N. Increasing N rates increase protein contents and reduce oil contents in canola seeds.